Aerofoil



Feb. 9;,"1'926 1,571,989

P, G. ZIMMERMANN AEROFOIL FiledMay 29, 1922 ,Patente-a Feb. 9,1926.

, UNITED- TESA PATENT" oFFicE.

rAUL e. ZIIMMEBMANN, oF xEYroET, NEW JERSEY, AssIGNoE To AEEQMARINE PLANE a Moron COMPANY, orl NEW Yoax, N.Y.,A coaroEAaIoNy or NEW Yoax.

AEROFOIL.

Application led May 29, 1922. Serial No. 564,281.

The invention is an aerofoil characterized by a section or contour which gives a greatly increased efficiency fora high speed wing. 'In' the accompanying drawing illustrating the invention:

Fig. l is an outline section of the aerofoil; and

Fig. 2 is a table.

In explanation of the-tableit mayA be stated that the chord is the portion of thel imaginary base line, touched `by the two lowest portions of thev bottom surface, which is includedbetween pe pendicula-rs from the leading and trailing e ges. Perpendiculars or offsets spaced at such arbitrary distances apart as will sufficiently define the curve are erected at stations 0 o 15, station 0 being at the leading edgeand 1'5 at the trailing edge. At the forward region, where the slopes aresteepest and where the form of the curves is most important, the stations are naturally nearest together.. The second column of the table shows the distance rearward from the leading edge of the several stations, expressed in per cents of the length ofthe chord. The third column shows the vertical distance from the chord of the points where the several perpendiculars intersect the upper surface or camber, also expressed in per cents of the chord The fourth column gives thel same data for the lower camber. v

Particular importance is attached to the contour in the upper camber, more especially between the leading'edge and the point ofmaximuincamber or elevation, which is at station-8. It will be seen that from the leading edge the surface rises in .a curve Aof decreasing upward slope to a point which isin the forward half of the aerofoil section and in advance of thefpoint of maximum marked 5, which is nearer the leading edge than the point of maximum camber, and 1n Chord .length ./Iarward from the leading sterms of the chord is ten per cent of thev edge. I do not, however, limit myself to precise dimensions and proportions. dipl should, however, occur within about the first 20% of the chord length. At the rear end of this forward curve, the surface rises again in a second curve or slope, this curve being shown as rising initially more steeply than the concluding portion of the first The y curve, though not sofsteeply as the initial portion of that curve, the second curve extending rearward in a comparatively long sweep with a gradually decreasing slope to the point of maximum camber at station 8, behind which it slopes downward toward the leading edge. This contour of the upper camber, characterized by the two curves or slopes, the continuity of which is interrupted by a break or dip, behind which the second slope rises in a hump to 4the greater height in rear, is of great advantage as stated, for a high speed wing. The precise form may cbe varied.

Other features and advantages of thewing n section will suggest themselves to those skilled in the art'.

What I claim as new is:

- l. An aerofoil, the upper cambered sur.- face of which rises from the forward region with a decreasing slope rearward to a point in advance of the region of maximum camber, and within about the first 20% of the chord 4at which point a longitudinally extending break or, dip in the curve occurs, from which the surfacey rises again in a second slope rearward toward the point of maximum camber.

2. An aerofoil, the uppercambered surface of which rises from the forward region with a decreasing slope rearward to a point in advance of the region of maximum camber and near the leading edge, at which point a. single longitudinally extending break or dip in the curve occurs, from behind which the surface rises again. in a second slope rearward toward the point of maximum camber.

3.' An aerofoil the generalv upper surface of which comprises a front curve extending rearward from the leading edge with a decreasing upward slopel to a point which is nearer the leading edge than the point'of the front curve and extends rearward with decreasing upward slope to the point of maximum camber beyond which it slopes downward toward the trailing edge.

4. An aerofoil the uppersurface of which consists of two distinct curves the meeting of which is marked by a longitudinally extending dip within about the rst 20% of the chord.

5. An aerofoil characterized by two slopes 10 chord, the second slope rising in a bump I5 behind said break.

PAUL G. ZIMMER-MANN. 

